This invention relates generally to the field of filtering devices used to cover drain openings to preclude ingress of undesirable particulate matter, such as sediment, debris, etc. More particularly, the invention relates to such filters used in conjunction with floor or ground mounted drains, such as for example storm drains found in roadways and paved areas, which have apertured grates covering the opening and preventing entry of relatively large objects.
It is often desirable or necessary to be able to quickly and easily cover storm drains and the like to prevent the ingress of undesirable particulate matter resulting from sudden storm events or the like. The drains comprise pipes or chambers that extend below ground and are connected to storm sewer systems, and the drains are covered by apertured grates positioned at the liquid ingress level, the apertures usually comprising numerous holes or elongated slots. It is known to provide filtering devices for the drain grates having a liquid permeable sheet member, either by anchoring the sheet member beneath the grate, by providing the sheet member in the form of an envelope that encases the grate member, or by securing the sheet member to the grate by ropes, straps or the like. These means and methods suffer from a common problem in that use of the drain grate cover requires handling the grate itself, which is time consuming and may lead to injuries due to the heaviness of the grate.
It is an object of this invention to provide a drain grate filter assembly that may be fastened securely to the grate quickly and easily without having to remove, lift and replace the grate. It is a further object to provide such a drain grate filter assembly that can be used in conjunction with any grate regardless of the positions, shapes or types of apertures found therein, such that the grate filter is generally universal in application. It is a further object to provide such a drain grate filter assembly in alternative embodiments such that the filter assembly is also applicable to storm drains disposed at curb inlets. It is a further object to provide such a drain grate filter assembly in another alternative embodiment wherein the filter assembly comprises an overflow opening surrounded by a berm such that water may pass thorough the opening in the event the filter media becomes liquid impermeable due to the accumulation of particulate matter.